1. Field of the Invention
The present invention relates to communication technology for transferring data through a network by the Simple Mail Transfer Protocol (SMTP).
2. Description of the Related Art
A method for transmitting data such as an image through a network includes an Internet facsimile (T. 37) for transmitting and receiving image data as an attached file of electronic mail (hereinafter “e-mail”) and a real-time Internet facsimile (T. 38) using a procedure of G3 FAX used by a telephone line.
When transmitting data, a destination is entered and an instruction is made to start the transmission. There is a demand that a user wishes to confirm whether or not a destination to which the data is actually transmitted is a correct destination. For example, in the case of the G3 FAX, a name corresponding to a telephone number transmitted from a recipient is acquired from a telephone directory of a transmitter and the acquired name is displayed. Alternatively, a name or the like is transmitted from the recipient to the transmitter using a unique procedure (Nonstandard Facilities (NSF) and Nonstandard Facilities Setup (NSS)), and the name or the like is displayed at the transmitter. However, even when information of a communication destination is displayed, a communication protocol proceeds. Thus, even when the displayed communication destination is incorrect, the communication proceeds and the data is transmitted.
In the case of the real-time Internet facsimile, the G3 FAX procedure is used directly. Therefore, in the same manner as the G3 FAX, even when the name or the like of the recipient to be a transmission destination is displayed, the communication protocol proceeds. Thus, it is not possible to carry out the transmission after confirming whether or not the transmission destination is correct.
In the case of the Internet facsimile which carries out transmission and reception using e-mail, normally, information of a destination cannot be acquired. The SMTP and the Post Office Protocol (POP) are used for the transmission and the reception of the e-mail. The e-mail is basically accumulated in an e-mail server by the SMTP. Depending on circumstances, the e-mail is transferred to another e-mail server and a destination device retrieves the e-mail from the recipient by the POP. Therefore, in case of the e-mail, communication cannot be carried out in real-time. Prior to the transmission of the data from the transmitter, information cannot be transmitted from the recipient to the transmitter. Therefore, prior to the transmission of the data, the transmitter cannot display the information of the transmission destination for confirmation. The transmitter can just transmit the data regardless of the status of the transmission destination. Even when the transmission destination cannot retrieve the e-mail, the transmitter cannot learn of such a fact.
For example, according to a conventional art, each of commands transmitted and received by a facsimile procedure is respectively transmitted and received as one e-mail, and the facsimile procedure is proceeded by exchanging e-mails. Accordingly, ability can be exchanged between one another, and information of the transmission destination can be acquired. Thus, the transmission destination can be confirmed. However, since each of procedures is carried out by exchanging e-mails, an extremely long period of time is required. In addition, since a large number of e-mails are exchanged, an order of the e-mails is required to be monitored and the e-mails are required to be distinguished from other e-mails received in other communication protocols.